now, the insanity defense is not unique. what is difference is what the attorney says caused this insanity. brutality of the chinese cultural revolution decades ago. >> a potential beautiful oriental vass from inception had a crack. >> that is what he calls the client. saying the 52-year-old experienced a break down down, when he shot and killed three executives. his head filled with flash backs he said from brutal abuse suffered during cultural revolution in china. >> they were considered traitors spit on and forced into hard labor. they never had enough food. >> murders happened november 14th. wu had been fired that morning. supposed to come back the next week to see if he can work instead as a consultant. police say he returned and shot the three in a meeting. sarah says he intended to shoot himself in front of boss autos they charged him. that is to disarm him. he doesn't remember pulling the trigger. >> prosecutors say it was revenge and that he planned murders and they say he bought a hundred bullets hours before gung